Per serving (142g) Calories 466, Fat 31g, Saturates 8.6g, Sugars 10g, Salt 0.81g
Preheat oven to 180°C (Gas Mark 4, 350°F) and line a baking sheet with parchment paper. Roll out the pastry on a lightly floured surface to a rectangle about 23cm x 30cm. Cut into quarters to create 4 individual rectangles and score a border on each, 1 cm from the edge. Transfer to the prepared tray.
In a small bowl, mix together the hazelnut butter, mustard, maple syrup, garlic and tarragon, and season well. Divide this mixture between the 4 tartlets, avoiding the borders. Arrange the carrots on top and brush the edges of the pastry with a little oil. Transfer to the oven and bake for 20 minutes, until risen and golden.
Serve hot or cold, sprinkled with chopped hazelnuts and some extra tarragon.